U.S. patent application number 10/450058 was filed with the patent office on 2004-04-08 for fuel cell for powering electronic appliances, in particular portable objects.
Invention is credited to Bloch, Didier, Delapierre, Gilles, Gauthier, Corrine, Laurent, Jean-Yves, Marsacq, Didier, Perut, Christian, Priem, Thierry.
Application Number | 20040067396 10/450058 |
Document ID | / |
Family ID | 8858126 |
Filed Date | 2004-04-08 |
United States Patent
Application |
20040067396 |
Kind Code |
A1 |
Bloch, Didier ; et
al. |
April 8, 2004 |
Fuel cell for powering electronic appliances, in particular
portable objects
Abstract
The fuel cell (2) is of the kind comprising an anode (12) and a
cathode (10) between which an electrolyte (18) is interposed. Solid
bodies (20) storing a hydrogen mass, able to be decomposed by
combustion, are associated to pyrotechnic means (24,26) to release
the hydrogen and bring it into contact with the anode (12). Means
(38) tap the ambient air to bring it into contact with the cathode
(10). Firing of the pyrotechnic means (24,26) is placed under the
control of addressing means (28) embedded in the appliance (2). The
surplus water produced by the exchange between the hydrogen and the
oxygen is resorbed by the temperature increase induced by
combustion of the bodies (20). The solid bodies (20) are supported
by an interchangeable card (22).
Inventors: |
Bloch, Didier; (Biviers,
FR) ; Delapierre, Gilles; (Seyssins, FR) ;
Priem, Thierry; (Seyssinet Pariset, FR) ; Marsacq,
Didier; (Grenoble, FR) ; Laurent, Jean-Yves;
(Claix, FR) ; Gauthier, Corrine; (Vert Le Petit,
FR) ; Perut, Christian; (Saint Fargeau, FR) |
Correspondence
Address: |
Oliff & Berridge
P O Box 19928
Alexandria
VA
22320
US
|
Family ID: |
8858126 |
Appl. No.: |
10/450058 |
Filed: |
July 9, 2003 |
PCT Filed: |
December 20, 2001 |
PCT NO: |
PCT/FR01/04092 |
Current U.S.
Class: |
429/416 |
Current CPC
Class: |
H01M 2300/0082 20130101;
H01M 8/04156 20130101; Y02E 60/50 20130101; H01M 8/00 20130101;
H01M 8/065 20130101; Y02E 60/32 20130101; H01M 8/0606 20130101;
Y02E 60/10 20130101; H01M 50/20 20210101 |
Class at
Publication: |
429/020 ;
429/034 |
International
Class: |
H01M 008/06 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 22, 2000 |
FR |
00/16941 |
Claims
1. A consumable device for providing electrical power, designed for
a portable electronic appliance and comprising a fuel cell
comprising an electrolyte (18) arranged between an anode (12) and a
cathode (10), means for storing hydrogen, means for conveying the
stored hydrogen to the anode (12), means (38) for tapping ambient
air and for bringing the tapped air into contact with the cathode
(10), means for controlling release of the hydrogen and means (38,
40) for neutralizing the surplus water produced by the cell, a
device characterized in that the means for storing hydrogen are
formed by at least one solid body (20) formed by a material
releasing gaseous hydrogen by combustion after firing by
pyrotechnic means (24,26).
2. The device according to claim 1, characterized in that the
material constituting the solid body (20) is a pyrotechnic
material.
3. The device according to one of the claims 1 and 2 comprising a
plurality of solid bodies (20), characterized in that the
pyrotechnic means comprise firing means (24) assigned to a
respective body (20), the control means (28,30) comprising means
for addressing (28) the firing means (24) associated to activating
means (26) of the latter.
4. The device according to claim 3, characterized in that
implementation of the activating means (26) is placed under the
control of means (30) for measuring the quantity of power available
for the appliance (2).
5. The device according to one of the claims 3 and 4, characterized
in that it comprises buffer means (36) for storing the power
supplied by the fuel cell, arranged between the latter and the
electronic means of the appliance (2).
6. The device according to any one of the foregoing claims,
characterized in that the means (38) for tapping ambient air are
means for causing the air to flow through an oxygen chamber (16),
one of the walls whereof is at least partially formed by the
cathode (10).
7. The device according to any one of the foregoing claims,
characterized in that the solid body (20) is housed in a
compartment (22) opening out into an expansion chamber (14) for the
released hydrogen, one of the walls whereof is at least partially
formed by the anode.
8. The device according to any one of the foregoing claims,
characterized in that the means (38,40) for neutralizing the
surplus water produced by the exchange between the hydrogen and the
oxygen are resorption means.
9. The device according to claims 6 and 8, characterized in that
the resorption means comprise any one of the ambient air flow means
(38) and means (40) for absorbing the water produced.
10. The device according to any one of the foregoing claims,
characterized in that the solid body (20) is housed in the
thickness of an interchangeable support (22), the different
elements, means and chambers of the device, with the exception of
the support of the solid body, being embedded in the appliance (2)
to be powered.
11. The device according to any one of the foregoing claims,
characterized in that the electrolyte (18) is a polymer membrane,
the electrodes (10,12) being formed from a carbon-based
material.
12. A fuel cell of a device according to any one of the foregoing
claims, said fuel cell being associated to electrodes (anode 12 and
cathode 10), with a fuel in the form of hydrogen, which is brought
into contact by means of an electrolyte (18) with a combustion
agent in the form of oxygen, characterized: in that the hydrogen is
stored inside at least one solid body (20) able to be decomposed by
combustion, the fuel cell comprising pyrotechnic means (24,26) for
firing the body (20) to release the hydrogen into an expansion
chamber (14) in contact with the anode (12), and that the oxygen is
tapped from the ambient air by means (38) for tapping this air and
for bringing the tapped air into contact with the cathode (10).
13. Application of a fuel cell according to claim 12 to supply of
electrical power to a portable electronic appliance.
14. A hydrogen reserve for a fuel cell according to claim 12,
characterized in that it comprises an interchangeable support
forming a receptacle (22) for at least one solid body (20) for
storing a hydrogen mass, this body (20) being able to be decomposed
by combustion and emerging from the support (22) to enable
expansion of the hydrogen released inside an expansion chamber (14)
situated inside the appliance to be powered, this support
comprising in addition: a) at least one firing means (24) assigned
to the body (20), b) activating means (26) for activating the
firing means, c) easily reversible means (32) for mechanical
connection to the appliance (2) to be powered.
15. A hydrogen reserve for a fuel cell according to claim 14,
characterized in that the support (22) comprises in addition
connecting means (32) operating in conjunction with conjugate
connecting means (34) of the appliance (2) to bring the activating
means (26) into contact with the control means (30) and addressing
means (26) embedded in the appliance.
16. The hydrogen reserve for a fuel cell according to claims 14 and
15, characterized in that the connecting means (32) and the means
for mechanical connection of the support (22) to the appliance (2)
are the same means.
17. The device according to any one of the claims 1 to 11,
characterized in that a selective membrane (51) is associated to
the anode (12,12') and is formed by a material enabling the solid
hydrogen storage bodies (20,20') to be isolated from humidity while
allowing hydrogen to pass.
Description
BACKGROUND OF THE INVENTION
[0001] The invention relates to the field of autonomous devices for
providing electrical power. The object of the invention is to
achieve such a device, that is consumable, for portable electronic
appliances, for example mobile phones or such like, or equipment
with an electronic memory or the like.
[0002] It relates more particularly to a consumable device for
providing electrical power designed for a portable electronic
appliance and comprising a fuel cell comprising an electrolyte
arranged between an anode and a cathode, means for storing
hydrogen, means for conveying the stored hydrogen to the anode,
means for tapping ambient air and for bringing the tapped air into
contact with the cathode, means for controlling release of the
hydrogen and means for neutralizing the surplus water produced by
the cell.
STATE OF THE TECHNIQUE
[0003] One of the objectives of designers of portable electronic
appliances resides in the light nature and small dimensions of
these appliances, in particular in order to make the latter easy to
transport and to handle. This objective must in particular take
into account the problem posed by the power supply means, normally
constituted by a relatively heavy and bulky rechargeable battery.
It is in fact apparent that increasing the autonomy time of the
equipment involves increasing the size and weight of these means.
This results in designers being subjected to the constraint of
having to find a compromise between the autonomy time of the
equipment and the space and weight set aside for the battery. It
should be noted that this compromise also has to take the
recharging time of the battery into account, which constitutes a
constraint for the user.
[0004] Prior art designers have therefore tended to concentrate
their efforts on batteries, such as lithium batteries, providing
the longest possible autonomy for a small size and weight. It
should however be noted that charging these batteries remains a
long operation and requires the use of a removable accessory, or
charger; this accessory imposes an additional constraint since the
user has to keep it close at hand, otherwise he will be unable to
recharge the battery.
[0005] According to another approach to the problem to be solved,
it has been proposed to equip portable electronic appliances with
consumable power supply means such as non-rechargeable batteries.
However, this solution presents the drawback of involving
prohibitive operating costs of the electronic appliance.
Furthermore, the disposable nature of these means, which comprise
toxic materials, also gives rise to inopportune waste treatment
costs.
[0006] Fuel cells for autonomous production of electrical power are
further known. These fuel cells associate electrodes (anode and
cathode) with a fuel in hydrogen form which is brought into contact
with a combustion agent in the form of oxygen by means of an
electrolyte. Conditioning the hydrogen used for these fuel cells
gives rise to a problem. According to a first proposed solution,
the fuel cells function by electrolysis of water to obtain the
hydrogen and oxygen necessary for their operation. According to
other solutions, hydrogen is formed by plasma reforming of gas or
methanol. This results in these fuel cells being difficult to
transpose for power supply of portable electronic appliances,
wherein they have to be embedded, due either to a difficulty in
matching the water reserve and the appliance or to an
incompatibility between the hydrogen production or storage means
and the constraints proper to portable appliances.
[0007] The documents EP-A-788,172 and GB-A-2,164,637 disclose the
use of a metallic hydride as hydrogen storage element.
OBJECT OF THE INVENTION
[0008] The general object of the present invention is to propose a
solution to the above-mentioned problem of size and weight of the
electrical power supply means of a portable electronic
appliance.
[0009] This objective is achieved by a device according to claim
1.
[0010] Going beyond this general objective, and starting off from
an initial inventive approach whereto the present invention
relates, the invention also more specifically has the object:
[0011] a) of proposing an autonomous device for supplying
electrical power to an electronic appliance, whose periods of power
delivery to the appliance are limited to the periods useful for the
latter,
[0012] b) of proposing consumable means for supplying electrical
power to an electronic appliance that are light, of small
dimensions, and easily treatable as waste,
[0013] c) of proposing a fuel cell whose structure is suitable for
being embedded in and for use by electronic appliances.
[0014] The inventive approach of the present invention consists in
a general manner in proposing to produce electrical power from an
embedded fuel cell, to supply a portable electronic appliance in
particular. The fuel cell proposed by the present invention
comprises the features whereby the hydrogen is contained in at
least one body made of a solid material able to be decomposed by
combustion, whereas the oxygen is taken from the ambient air by
means for tapping this air.
[0015] The hydrogen is releasable by pyrotechnic means that cause
firing of the solid material with a view to decomposition thereof.
It should be noted that these pyrotechnic means are associated to
control means for implementation thereof.
[0016] According to another feature of the invention, there are
preferably provided a plurality of solid bodies, each one being
independent from the other, connected to a respective firing means
that the pyrotechnic means comprise. These arrangements are such
that the global quantity of hydrogen contained in the device is
progressively released by distinct firing of the different solid
bodies. According to this feature of the invention, the control
means comprise in particular means for addressing the firing means
that are associated to activating means. Implementation of the
latter means is advantageously placed under the control of means
for measuring the quantity of power available for the appliance.
Delivery of power for the appliance takes place when a minimum
available power threshold is detected and/or when an operation to
be performed by the appliance requires power to be supplied.
[0017] It should be noted that in the preferred case where there
are a plurality of solid bodies, the latter can each contain the
same quantity of hydrogen, or respective quantities of hydrogen.
The advantage can be noted in the latter case of enabling hydrogen
to be delivered in a quantity suitable for a punctual requirement,
by firing of a specific body ordered by the addressing means
advantageously placed under the control of the means for measuring
the quantity of power available for the appliance.
[0018] The residual water surplus to requirements that is produced
in the course of the electrochemical reaction between the hydrogen
and oxygen is neutralized by resorption means. These means
advantageously comprise the above-mentioned pyrotechnic means, in
that they cause a temperature rise causing evaporation of the water
produced. It should be noted that these resorption means are if
necessary accessorily completed by means for absorbing the water
produced, such as a porous or alveolar body. It can thus be noted
that the arrangements of the invention enable spontaneous use of
the residual water for operation of the combustion cell of the
invention, the surplus being neutralized. This spontaneous use
resides in particular in keeping the electrodes and electrolyte in
a moist environment and in protecting the appliance from a too
large heat increase. It should also be noted that these
arrangements improve the efficiency of the combustion cell of the
invention.
[0019] The means for tapping the ambient air are preferably means
causing a flow of the air surrounding the device, such as by
suction and/or discharge, through an oxygen chamber one of the
walls whereof is at least partially formed by the cathode. These
arrangements are such that the cathode is placed in contact with
the ambient air and more particularly with the oxygen contained by
the latter.
[0020] In the embodiment wherein the tapping means are ambient air
flow means, the latter in addition advantageously at least partly
constitute the above-mentioned water resorption means, in so far as
they cause a current for conveying this water, evaporated or not,
to means for removing the water from the device, and/or accessorily
to the above-mentioned absorption means. It should also be noted
that these ambient air flow means enable an inopportune temperature
rise to be prevented.
[0021] The solid body containing the hydrogen is for its part
housed inside at least one compartment. According to the preferred
embodiment wherein a plurality of solid bodies are provided, the
latter are housed, according to different variants, either in a
respective compartment or in a global compartment, or if applicable
in compartments housing the bodies by respective groups depending
on the quantity of hydrogen they respectively contain. This
compartment opens out into an expansion chamber for the released
hydrogen, one of the walls whereof is at least partially formed by
the anode.
[0022] The proton exchange between the anode and the cathode takes
place by means of an electrolyte interposed between these two
elements. The electrodes are made to come into contact with
conjugate connection means of the appliance to be supplied. The
appliance can, according to various alternative embodiments, either
have the power supplied available directly or be equipped with
buffer means for storing the power supplied by the fuel cell, in
order to regulate use of this power by the appliance. These buffer
means are in particular arranged between the fuel cell and the
electronic means of the appliance provided for power supply
thereof. It must be understood that in the latter case, the buffer
power storage capacity of these means is as such low in comparison
with that of the similar means equipping portable electronic
appliances of the prior art.
[0023] It should be noted that these buffer power storage means are
advantageously associated to the above-mentioned means for
measuring the quantity of power available for the appliance.
[0024] To return to a general structural definition of the present
invention, the proposed device is a consumable device for supply of
electrical power for a portable electronic appliance. This device
is mainly constituted by a fuel cell comprising:
[0025] a) at least one anode and at least one cathode between which
there is interposed an electrolyte which is assigned thereto per
couple,
[0026] b) at least one solid body storing a hydrogen mass, this
body being able to be decomposed by combustion,
[0027] c) means for tapping the ambient air surrounding the support
and for bringing the tapped air into contact with the cathode,
[0028] d) pyrotechnic means for firing the body to release the
hydrogen and bring it into contact with the anode,
[0029] e) means for commanding firing of the pyrotechnic means,
[0030] f) means for neutralizing the water produced by the exchange
between the hydrogen and the oxygen,
[0031] g) means for bringing the electrodes and the power supply
circuit of the appliance into contact with one another.
[0032] This results in the portable electronic appliance being
supplied with electric power in complete safety for the appliance
and its user from an autonomous and consumable power production
source.
[0033] According to an important feature of the present invention,
there is preferably provided a plurality of solid bodies. The
pyrotechnic means comprise a corresponding plurality of firing
means assigned to a respective body. The control means comprise
means for addressing the plurality of firing means associated to
activating means of the latter. It should be noted that by means of
these arrangements, it is envisageable to advantageously place
implementation of the activating means under the control of means
for measuring the quantity of power available for the
appliance.
[0034] It should however be noted that this implementation can,
independently or in combination, advantageously be controlled on
demand by the user by means in particular of a corresponding manual
control means.
[0035] According to another feature of the invention relating to a
convenience of use of the device, the solid body is housed in the
thickness of an interchangeable support, in particular flat such as
in the form of a card. It should however be noted that the shape of
the support can be taken advantage of to improve the efficiency
and/or capacity of the fuel cell of the invention. This card is
advantageously in the format of an ordinary credit card (with a
surface of about 46 sq.cm for a thickness of about one millimeter).
This card is interchangeable to enable it to be replaced when the
hydrogen reserve has been used up. It can be understood that the
different elements, means and chambers of the device, with the
exception of the support of the solid body, are advantageously
embedded in the appliance to be powered. However, it should be
noted that according to another possible alternative embodiment,
and without departing from the general rule of the invention as
described, all the means of the device of the invention can be
embedded in a globally interchangeable support. In this case, the
means for bringing the electrodes into contact with the
distribution circuit proper to the appliance are formed by means
for connecting the electrodes to the corresponding means of the
appliance. These connecting means, and means for connecting the
pyrotechnic means to the control means should these be necessary,
are then emergent from the support.
[0036] The invention, according to another approach, therefore also
relates to a hydrogen reserve for a combustion cell, comprising an
interchangeable support advantageously in the form of a card. This
support forms a receptacle for at least one solid body for storage
of a hydrogen mass, this body being able to be decomposed by
combustion and emerging from the support, for the purposes notably
of enabling expansion of the hydrogen released inside an expansion
chamber situated inside the appliance to be powered. This support
comprises in addition:
[0037] a) at least one firing means assigned to the body,
[0038] b) activating means for activating the firing means,
[0039] c) easily reversible means for mechanical connection to the
appliance to be powered.
[0040] It should be noted that the assembly between the support and
the appliance is tight, the appliance or alternatively the support
comprising for example tightness means to confine the support
inside the hydrogen expansion chamber arranged in the
appliance.
[0041] With relation to the above-mentioned preferred embodiments,
the support comprises in addition connecting means operating in
conjunction with conjugate connecting means of the appliance to be
powered to bring the activating means into contact with the control
means, or the addressing means, embedded in the appliance. It can
be noted that these connecting means and the above-mentioned means
for mechanical connection of the support to the appliance are
advantageously the same means.
[0042] It should be noted that the electrolyte is for example a
polymer membrane, such as Nafion (Dupont de Nemours registered
trademark). As for the electrodes, they are for example formed from
a carbon-based material.
[0043] According to another approach of the invention, the latter
also relates to a fuel cell as such. Indeed, unlike usual practice
in this field, the hydrogen is provided not by electrolysis of a
water reserve or from a reserve of material under pressure for
example, but from solid bodies able to be decomposed by combustion.
This fuel cell can therefore be recognized in general in that the
hydrogen is stored inside at least one solid body able to be
decomposed by combustion, the fuel cell comprising pyrotechnic
means for firing the body to release the hydrogen into an expansion
chamber in contact with the anode. The oxygen is for its part taken
from the ambient air by means for tapping this air and for bringing
the tapped air into contact with the cathode.
[0044] Due to these arrangements, the fuel cell is viable in
complete safety for an application for supply of electrical power
to a portable electronic appliance, both on account of the fact
that there is hardly any water present and of the secured storage
of the hydrogen reserve.
BRIEF DESCRIPTION OF THE DRAWINGS
[0045] The present invention will be better understood and details
relating thereto will become more clearly apparent from the
following description of preferred embodiments with reference to
the figures of the accompanying drawings in which:
[0046] FIGS. 1 to 3 are schematic representations of devices
according to respective alternative embodiments of the
invention.
DESCRIPTION OF A PREFERRED EMBODIMENT
[0047] In the figures, a fuel cell designed to equip a portable
electronic apparatus 2 can be seen. At least one anode 12,12' is in
contact with the internal volume of a hydrogen expansion chamber
14,14' whereas at least one cathode 10,10' is in contact with the
internal volume of an air flow chamber 16,16' that contains oxygen.
At least one electrolyte 18,18' is interposed between each anode
and cathode couple 10,12 and 10',12'.
[0048] A set of solid hydrogen storage bodies such as 20,20' are
arranged in a middle zone forming a compartment 22. Ignition means
24,24' are assigned to each of these bodies 20,20' for selective
combustion thereof by activating means 26 controlled by addressing
means 28. These addressing means 28, comprised in the electronic
means of the appliance 2 to be powered, are themselves placed under
the control of means 30 for measuring the power available for the
appliance.
[0049] The solid hydrogen storage bodies 20,20' release gaseous
hydrogen by slow combustion. They may be formed by a pyrotechnic
material releasing hydrogen by combustion when it is activated.
[0050] It can be noted that the connecting means 32 related to the
pyrotechnic means 24,26,28 are provided to operate in conjunction
with conjugate connecting means 34 of the appliance 2 to be
powered. It can also be noted that the appliance 2 accessorily
comprises a buffer power reserve 36 interposed between the
appliance 2 and the fuel cell of the invention to regulate the
power supplied to the appliance in operation.
[0051] Moreover, the cell of the invention comprises means 38,38'
for tapping ambient air and for bringing this air into the oxygen
chambers 16,16'. These means 38,38' are for example means causing a
natural air flow inside these chambers 16,16', such as by venturi
effect. Filtering grates 46 prevent undesirable particles from
getting in.
[0052] The surplus water produced by the exchange between the
hydrogen and oxygen and not used by the device is resorbed by
evaporation. This evaporation is caused by the temperature rise
resulting from combustion of the bodies 20,20' and from the heat
given off by the electrochemical reaction. The water vapour is
expelled from the fuel cell by the tapped ambient air flow means
38,38'. It should be noted that the water absorption can be
completed by absorbent means, such as 40,40'.
[0053] In the alternative embodiment illustrated in FIG. 3, all the
means of the fuel cell are supported by a common removable support
4. In the preferred embodiments illustrated in FIG. 1 and FIG. 2,
only the hydrogen reserve is supported by a removable support 22,
the rest of the means of the device of the invention being embedded
in the appliance 2.
[0054] In FIG. 1 and FIG. 2, the appliance comprises a housing for
tightly receiving the support 22 of the solid bodies 20. Tightness
is achieved for example by means of seals, such as 42 or 44, which
are in particular interposed between the support 22 and the
appliance 2, and at the ends of the electrodes 10,10' and 12,12'.
It can be understood that the support, which corresponds to the
compartment 22, forms a receptacle for the solid bodies 20 that
emerge therefrom. This support 22 is presented in the form of a
flat support having the shape of a commonplace credit card.
[0055] According to the embodiments of the support 22 illustrated
in these figures, this support has a volume of about 3.5 to 4
sq.cm. Such a support, on account of the inert packaging and
sectoring materials, enables a quantity of solid hydrogen storage
material of about 0.4 grams to be housed. This results in a
potential quantity of releasable hydrogen of about 0.052 grams,
enabling 0.53 Wh of electrical power to be delivered. Such a
delivery corresponds, for a cellphone for example, to a time of use
of about two hours of conversation under nominal operating
conditions.
[0056] A selective membrane 51 is associated to the anode 12,12'
and is formed by a material enabling the solid hydrogen storage
bodies 20,20' to be isolated from humidity while allowing H.sub.2
to pass.
[0057] In FIG. 3, connection means 6,6' emerge from the support 4
to operate in conjunction with similar connection means 8,8'
equipping the appliance 2 for supply of power thereto.
* * * * *